Devices to micro-fabricate a sample precisely include a focused ion beam (hereinafter called FIB) milling device. The FIB milling device irradiates a sample with an ion beam focused to sub-micron order while scanning the ion beam by electrostatic deflection, thus processing the sample at a target position into a desired shape.
Such processing using an ion beam needs sufficient knowledge about constituent elements, for example, of a sample to be processed. This is because the sputtering yield [μm3/nA·s] of the ion beam depends on the constituent elements.
When the materials and the structure of a sample are known, a skilled worker firstly finds the sputtering yield therefor, decides a relation among a beam current of the FIB milling device, beam residence time (hereinafter called dwell time) per unit area, and a milling depth, and then processes the sample.
On the other hand, when the materials and the structure of a sample are uncertain, a skilled worker analyzes the constituent elements or checks the design beforehand to decide an area to be processed, and then actually processes the decided area to be processed. By repeating this operation, the skilled worker creates the fabrication procedure to achieve a desired shape.
When the materials and the structure of a sample are uncertain, a FIB beam at a low energy level has to be used for the FIB milling. This means a low processing speed of the milling. The FIB milling further needs to successively change the conditions depending on a material appearing on the surface of the sample and a change in shape of the sample during the milling. Therefore the finished quality of the sample often depends on the skill of the worker.
One of FIB devices available enables the analysis of constituent elements of a sample using an energy dispersive X-ray spectrometer (EDS) while processing the sample by a FIB (see Patent Literature 1).